Bonding clamp



May 23, 1933. B, EGG 1,910,022

BONDING CLAMP Filed May 22, 1951 Buell yj amg Cil.

Patented May 23, 1933 unirsi) sTAfres Par-'ENTE' oFFicEj y BUELL` 3. Lees, or coLUi/iisirs, voiiro, Assienon -'ro coiLUiviBiAENGINEEnING AND MANAGEMENT ooiironA'rIoN, or orNcINjNA'rI, oHIo; AconronA'rIoN or oHIo' nonnina CLAMP Appucatio mea May 22, 193,1. seriai N. 539,330.

This invention relates to aniinproveinent in safety bonding clamps which is adapted primarily for use by workmen in severing,

disconnecting or otherwise coupling and uncoupling metallic pipes used in conducting inflammable fluids, to minimize the possibilities of accidents through explosions -pro. duced by stray electric currents passingl through such pipes. It is thereforean out-` standing object ofthe invention toprovide a device which may be readily adaptedto pipe lines without interferingwith the workmen, when connecting or disconnecting such pipe lines where stray electric current may` be present or suspected. .Y a

The longitudinal flow of stray electric current on pipe lines has long been recognized as one of the severestk corroding agents that metallic pipe users face. Those dealing with the problem are aware that the combination ot electricity and gas, using a commoncar-j i'ier such as a pipe line, hasy highly undesir` able potentialities from a` saetystandpoint,

and efforts are being made to educate those whose duties are directly concernedwith the construction and repair ot gas linesparticularly in order to warn them of-this littleknown danger.'` Vhen .a pipeline or other" continuous metallic structure having a cur-` rent of appreciable value moving upon it;

issevered, the tendency'is for a spark-to'be created between the separated parts. The intensity of this spark depends upon thecur'- rent density of the conductor; the difference in voltage Vbetween the separated, parts, and to an extent upon the condition'of thesevered ends, particularly where the structure is a pipe. m

The workmans` experienceand the methods used in joining or cutting thepipe :in the trench will be .contributing factors and may tend to increase errdecrease the attendant risk. It follows that. an inexperienced crew-,; finding it necessary to fumble a Joint in re: moving it, increase the risk byimalre and brealr'contacts `which suchyan operationn invites iii the eventcurrent is. present; causing, quite frequently', theV generation of as number of sparks, Vanyor all of which; may be sutlici'ent to igniteleaking gas.

In vcommunities having electric railwayV service, the danger is more acuteif a pipe line, having screw, weld, orother metal to metal joints, is the structure under construc tionrdue tothe smaller electricall resistance ofjoints of this type, and the consequent easierpath oifered the flow of current.,vv Noi` vare the transmission and production lines :tarpreinovedV from yelectric railwaytracks exempt from the flow Vof stray current.y Transmission lines, other `than thosev having certain types of rubber ring couplings, due totheir size and length, often collect from the earth and conduct relatively -a large amount of stray current, and because of their remoteness from trolley operations are apt to give a repair crew a t'alse sense of security. Particularly is this true in localities where coalminfes are operating small electric mine4 cars and other equipment. There the source` offcurrent is even less apparent and quite frequentlyaects wells, production lines and transmission lines overa large area.

With this safety factor in mind, I have produced a quickly attachable and removable device which may be applied to a pipe line,

adjacent to a' point where it is to be connected or disconnected, for the purpose of providinga small resistance path for any current flowing on the pipe line, allowing such current to be shunted around the separated pipe ends` I` am aware of the fact that itV has been proposed heretofore to accomplish this result but my present bonding clamp is intended to supplant and to improve upon such earlier and mechanically more cumbersome appliances `or methods, such as f the compression screw tool, orthe practice of filingor abrading the pipe and wrapping wire around a clean portion, all of which are highly unsatisfactory. y Y

It is another object of the invention to provide aibonding clamp; for thejpurpose set forth constructed of a highly resilient metal,

such as saw steel and provided with spaced resilicntjaw's, which carry opposed inserts having machined pipe engaging points, and

in vaddition toL provision being made for` tightening the jaws of the clamp around the pipe, whereby the points engage with the' pipe surfaces to secure a good electrical contact therewith, irrespective of coatings on the pipe, the clamp being further provided with adjustable screw means for positively forcingthe points into the pipe independent in addition to thenormal resiliency of the jaws.

It is another object of the invention to providev a bonding clamp appliance consisting l disconnection.

` diameters.

It is a further object of the invention to provide a bonding appliance of this character wherein the individual clamp members are oi such form that they may be readily adapted to pipes lpossessing widely differing An additional object resides in constructing each of the clamp members so that while they possess suiicient metallic strength to" enable them tol readily hold up under the severe usage due to field operations, yet at thesa-me time, they will possess the capabilimember ties of good electrical conductors.

With these and other objects -in view,

which which appear as the description proceeds, the invention consists in the novel features of construction, combination of elements and arrangements of parts hereinafter fully described and pointed out in the appended claims.

In the accompanying drawing: Fig. 1 is a view in end elevation of one of the clamp members employed in my im` proved bonding appliance;

Fig. 2 is a side elevation of vsaid clamp:

Fig. 3 is a horizontal sectional view on the plane indicated b-y the line 3 3 of Fig. 1;

Fig. -l is a side elevation disclosing a pai-r of-'clamping members, comprising the complete bonding appliance, mounted on a pai-r ofadjoining pipe ends and disclosing the position ofthe bonding vappliance in practice' l l 5 is a transverse Ysectional view-'on the 'i line 5 5 of Fig. 4. i

Referring more particularly to the drawing, the numeral 1 designates my improved bonding appliance in its entirety. In its preferred embodiment, this appliance consists of' a pair of spaced clamping members 2 2' which are united by one or more flexible elec- Y trical conductors 3.

Each oi the clamping members isv formed to comprise a spring steel strip formed cen-` trally of its length to produce a circular eye;

ency.

portion 4 which terminates in spaced downwardly extending side walls 5, and the latter, in turn, terminate in outwardly bowed resilient jaws 6 6 of desired curvilineal form, the lower ends of said jaws terminating in rounded extremities 7, which permit of the ready application of the clamp to a pipe. The clamps are preferably formed from a steel, such as saw steel, in order tl'iatthey will possess inherently a desired degree of resili- To improve the current conducting properties ofthe clamp, I apply to the outer surfaces of each of the jaws 6 arcuate copper plates designated by the numeral 8. These plates possess a slightly greater curvature than that normally imparted to the aws 6. To insure a good electrical contact between the jaws and apai-r of separablepipe ends, indicated at 9 9, I provide'the interior ofthe jaws with a plurality of inwardly directed steel pins l0, which are provided with sharp, penetra-ting machine points, which are adapted to pass through coatings, if present, on the pipe ends, so that the points will penetrate into the metal structure of thepipes, to which the clamps are attached, to secure proper Inechanical and electrical contact. The larger ends of the pins are provided, as shown in Fig. 3, with threaded bores which are adapted for the reception of headed fastening screws 11, and these screws when tightened serve to hold the pins 10 and the copper plates 8 in rigid secured relationship with the jaws 6, insuring good contact between vthe screw heads and the copper plates and in addition, formingv av lock for the screws by the relative differences in curvature of the aws 6 and the plates 8. 1

Tov further procure the desired contactbetween the pointed ends ofthe pins 10 and the pipes 9, in addition to the pressures supplied totheV normal resiliency of the jaws 6 and the associated eye portion 4.-, the walls' of the clamp members are formed with registering openings through which passes a tightening screw 12. The threaded end of this screw isV provided with a wing nut or its equivalent 13. The headed end of the screw'is provided with a washer and positioned between this washer and the adjoining wall 5 and surroundingfthe screw 12' is a coil spring 14:. Likewise, engaging with the wing knut 13 and positioned on` the screw 12 isl a washer, and located between this washer and the adj oining'side wall 5, and surrounding the screw 12 is a complementary spring' 14. In l practice, the -wing nut 13 is moved outwardly on the screw 12 to adesired extent and the jaws 6 are separated so that each clamping vmember may behapplied around the pipes 9, as shown in Figs. 4 and 5, with the pointed ends of the pins 10 in contactx with-*said pipe members. Then, by

tighteni-ngthe nut 13, additional pressures are created which serve'to draw. the jaws 6 inwardly so that the pins l() will be moreA positively brought into penetrating engagement with the pipe walls. Headed screws 15 pass through the upper ends of the jaws 6 and the plates 8 and have their outer portions provided with binding nuts 16. These fastening elements are used to secure a current conductor 17 in connection with the upper ends of the plates 8 of each clampand also provide a fastening for securing the Jterminal portions of a vflexible conductor 18 througl which current passes from one clamp to the other. This forms a low resistance shunt circuit for the pipe current, which under ordinary circumstances, is sufficient to reduce the difference in potential between the sepa- Y rated structures and prevent to a large extent the tendency for a sparl to be formed at any point on the structure spanned by the two clamps. The clamps, being primarily self adjusting, are easily placed on a pipe, spanning the pipe where a cut is to be made or where a connection is to be completed, and each clamp is rocked bacl and forth slightly in order to allow the hardened steel Contact points on the pins l0 to penetrate any high resistance coating covering the metal.

The facility with which these clamps,

lwhich may be of any size, may be. applied to pointed pins protruding from the inner surj' faces of said jaws to engage with the pipe member, fastening devices for securing said conductor plates and pins to said jaws, a flexible conductor uniting said plates, and manually adjustable threaded means for positively drawing said jaws and pins into clamping engagement with the pipe member.

2. A bonding clamp of the character'described, comprising a flat metallic strip bent longitudinally and centrally uponritself to form a loop which terminates in a pair of spaced arcuate resilient jaws shaped to surround a pipe member, arcuate conductor plates carried by said jaws, inwardly proj ecting pointed pins protruding from the inner surfaces of said jaws to engage with the pipe member, removablefastening devices for securing saiflconductor plates andV pins to said jaws, a liexible conductor uniting said plates, a second conductor connected A' with at least one of said jaws, and manually adjustable threaded means for drawing said jaws and pins into'clamping 'engagement with the pipe member. v

3. A bonding clamp of the charatcer described, comprising a flat comparatively thin metallic strip bent longitudinally and centrally upon itself to form a loop which terminates in a pair-of spaced arcuate resilient jaws shaped to surround a pipe member, arcuate conductor plates carried by the outer surfaces of said jaws, inwardly projecting pointed pins protruding from the inner surfaces of said jaws to engage with the pipe member, threaded fastening devices for securing said conductor plates and pins to said jaws, a flexible conductor uniting said plates, a second conductor connected with at least one of said aws, a bolt passing through said jaw membersat a point adjacent said loop, a spring on said bolt, and manually adjustable threaded means for applying tension to said spring and jaw members when vin a clamping position upon the pipe member.

In testimony'whereof I alx my signature.

BUELL B. LEGG. 

